In a large pot, cook bacon over medium-high heat until crispy. Using a slotted spoon, transfer the bacon to a paper towel-lined plate; set aside.
Add the onion, celery, and carrot to the pot with the reserved bacon grease. Sprinkle with salt and pepper. Cook, stirring often, for 5-6 minutes, or until the onion is translucent and tender. Add the garlic and thyme to the pot. Cook, stirring often, for an additional 2 minutes.
Add the flour to the pot. Cook, stirring constantly, for 1 minute. Add the beer, chicken stock, heavy cream, Dijon mustard, and Worcestershire sauce; stir to combine. Bring the mixture to a boil and allow the soup to thicken. Once the soup thickens a bit, turn the heat down to medium-low and allow the mixture to simmer for 8 minutes.
Turn off the heat and slowly stir in the cheese. Season with salt and pepper to taste.
Garnish with crispy potato croutons, sliced scallions, and crumbled bacon. Serve immediately.
Potato Croutons:
Preheat oven to 425°F.
Add potatoes to a small bowl. Drizzle with olive oil. Add salt, pepper, smoked paprika, and Italian seasoning; Stir to coat the potatoes.
Transfer the potatoes to a baking sheet. Bake for 15-20 minutes, or until the potatoes are golden brown and crispy on all sides.
Notes:
If you're not going to serve immediately, transfer the cooled soup to an airtight container and place in the refrigerator for up to 3 days. Reheat on the stovetop or in a slow cooker.
If you're making and serving a crowd, transfer the hot soup to the bowl of a slow cooker and select the "Keep Warm" setting. Stir the soup occasionally to prevent browning around the edges.